From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932627Ab0HXWyi (ORCPT ); Tue, 24 Aug 2010 18:54:38 -0400 Received: from kroah.org ([198.145.64.141]:52329 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932387Ab0HXWy1 (ORCPT ); Tue, 24 Aug 2010 18:54:27 -0400 X-Mailbox-Line: From gregkh@clark.site Tue Aug 24 15:25:26 2010 Message-Id: <20100824222526.676650737@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 24 Aug 2010 15:25:01 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Matt Evans , Benjamin Herrenschmidt Subject: [49/59] powerpc: Initialise paca->kstack before early_setup_secondary In-Reply-To: <20100824224625.GA5449@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Matt Evans commit f761622e59433130bc33ad086ce219feee9eb961 upstream. As early setup calls down to slb_initialize(), we must have kstack initialised before checking "should we add a bolted SLB entry for our kstack?" Failing to do so means stack access requires an SLB miss exception to refill an entry dynamically, if the stack isn't accessible via SLB(0) (kernel text & static data). It's not always allowable to take such a miss, and intermittent crashes will result. Primary CPUs don't have this issue; an SLB entry is not bolted for their stack anyway (as that lives within SLB(0)). This patch therefore only affects the init of secondaries. Signed-off-by: Matt Evans Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/head_64.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -563,9 +563,6 @@ __secondary_start: /* Set thread priority to MEDIUM */ HMT_MEDIUM - /* Do early setup for that CPU (stab, slb, hash table pointer) */ - bl .early_setup_secondary - /* Initialize the kernel stack. Just a repeat for iSeries. */ LOAD_REG_ADDR(r3, current_set) sldi r28,r24,3 /* get current_set[cpu#] */ @@ -573,6 +570,9 @@ __secondary_start: addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD std r1,PACAKSAVE(r13) + /* Do early setup for that CPU (stab, slb, hash table pointer) */ + bl .early_setup_secondary + /* Clear backchain so we get nice backtraces */ li r7,0 mtlr r7